The Family Unit in JKR's Wizarding World

This is something that's been bugging me since I finished reading the series and today I finally sat down to see if my hunch was right. It appeared to me that there is, um, no divorce in the wizarding world. And children are almost never raised by one parent -- there's Luna (whose mother died), and Hagrid (whose mother left him because she wasn't even human and so "not very maternal"), but that's about it.

Tom Riddle is raised in an orphanage, and Dean Thomas has a (step?)father as per DH, as, probably, does Blaise Zabini (as per HBP where his mother is cited as marrying a lot in general).

Needless to say, I find this extremely o.O-inducing.

I've left out everyone about whose family situation we know nothing, but here is a listing of HP characters and their parental arrangements. I've cited chapters here and there, but I'm going mostly by memory and so most of the time, I've cited just books.

Abbott, HannahWhen her mother died during HBP, she left Hogwarts. It is not stated whether she had a father, but presumably she had someone to go to when she left the school.

So out of 44 families whose situation is known, 33 (a full 75 per cent) are clearly traditional two-parent families. For 7, status is impossible to determine, 2 are widower!single parents and only 2 are "other parent left" type single parents. That's four per cent.

In other words, the only explicit instances of single parents who isn't widowed are those of Merope Gaunt (whose child is born evil) and Hagrid's father, whose 'wife' was not even human.